1. Field of the Invention
The present invention relates to techniques for determining sensor positions and improving the spatial resolution of measurements performed with these sensors. More specifically, the present invention relates to arrays of sensors that utilize lateral inhibition when communicating with one another.
2. Related Art
Many measurement and monitoring systems include distributed arrays of interacting sensors, which are also known as sensor networks. For example, sensor networks are used to perform measurements of parameters such as temperature and humidity or to monitor intrusion across virtual borders in a variety of environments. In order to provide useful information in these applications, the locations of the sensors often need to be known or inferred. However, the use of pre-determined sensor locations is not possible in an increasingly popular category of sensor networks that allow random or ad hoc sensor placement. In these networks, the sensor positions need to be determined after the sensors are distributed in a region.
While there are many existing localization techniques that may be used in sensor networks, these approaches are often unattractive due to additional system constraints, such as power requirements, limitations on onboard resources (for example, the processor speed or the amount of memory), cost, as well as maintenance and reliability restrictions. For example, in one existing approach sensor positions may be determined using acoustic and radio signals. However, this technique uses multiple base stations as well as high-frequency transmitters and receivers that are expensive and consume significant power. Another existing approach localizes sensors using variations in the strength of radio signals as a function of distance. Unfortunately, effects such as noise, interference, multi-path signals, and the difficulty of determining strength changes at very close range have limited the efficacy of this technique.
Furthermore, allowing random sensor positions may have consequences for the spatial resolution of measurements performed by sensors in an ad hoc sensor network. In particular, the spatial resolution of an array of optical sensors may depend on the sensor density for a given intensity of incident light. When the sensor placement, and thus the sensor density, is random, it may therefore be difficult to achieve a desired or optimal spatial resolution from the array.
Hence, what is needed is a method and an apparatus that facilitates determining sensor positions in a sensor network and that facilitates adjusting of the spatial resolution of measurements performed using the sensor network without the problems listed above.